annis etal



M. R- ANNIS ETAL 2 Sheets-Sheet 1 WATER PACKER FIG- 25 MUD INVENTORS.LEON H. ROBINSON, JR ROBERT H. FRIEDMAN BY MAX R. ANNIS,

S G U L P L L A B FIG. 2.

ATTORNEY.

March 3, 1964 FREEING PIPE STUCK IN A BOREHOLE Filed March 1, 1962 PERMEABLE ZONE 4 DRILL P|;PE

PA 0 KER 9 DRILL COLLARS March 3, 1964 M. R. ANNIS ETAL 3,123,143

FREEING PIPE STUCK IN A BOREHOLE Filed March 1, 1962 2 Sheets-Sheet 2FIG- 5- INVENTORS. LEON H. ROBINSON JR., ROBERT H.FRIEDMAN,

BY MAX R. ANN|s,

wJJM/Lm ATTORNEY.

3,123,143 FREEING FEE STUCK IN A BQREHGLE Max R. Annis, Leon H.Robinson, Jr., and Robert H.

Friedman, Houston, Tex., assignors, by mesue assi ments, to JerseyProduction Research Company, Tulsa,

Okla, a corporah'on of Delaware Filed Mar. 1, 1962, Ser. No. 176,591 4Claims. (Cl. 166-187) This invention relates to appmatus for isolating asection of a borehole, and more particularly to apparatus for looseningand freeing a drill pipe stuck against a borehole wall by differentialpressure between the borehole and an earth formation penetrated by theborehole.

In boreholes drilled for the punpose of recovering oil and gas fromproductive earth formations, it is customary to circulate a drillingfluid down a drill pipe and up the annulus thereabout for the purpose ofremoving earth cuttings and generally facilitating drilling operationsIn order to prevent blowouts, it may be necessary to make the drillingfluid quite heavy. As a result, a very large pressure difierential canexist between the interior of the borehole and the earth formationspenetrated thereby. It is not uncommon for drill pipe to become stuckagainst the walls of a borehole as a result of this pressuredifferential. Oftentimes the pressure differential is so high that it isnot even necessary for the drill pipe to break through the filter cakelining the walls of the borehole in order for the pipe to become stuck.Generally speaking, it is the lower part or" the drill string includingthe so-called drill collars that is most susceptible to differentialsticking as described above. The general problem is discussed in U.S.Patent 2,865,454, Richards, and in an article at page 201 of theperiodical Oil and Gas Journal, vol. 49, No. 39.

In accordance with the present invention, a fluid expansible packer isaffixed to a section of a drill string, which packer is adapted toexpand to the sides of an earth formation penetrated by the drill stringso as to seal the space between the drill string section and the wallsof the borehole. First passageway means are provided within the drillstring section between the bore of the section and the interior of thepacker so that the packer can be inflated by fluid from within the drillstring section. A normally-closed first valve means is provided fornormally closing the passageway to fluid flow therethrough until thedifferential pressure between the section and the borehole annulustherearound is of a first given magnitude. In parallel with the firstvalve means is provided a second, normally-closed valve means adapted toopen when the pressure between the bore of the drill string section andthe annulus around the section immediately above the packer is of asecond given magnitude higher than the first given magnitude mentionedabove. The second valve is adapted to remain open after release of thepressure opening it for a predetermined period of time suflicient forthe packer to contract to its normal position after pressure has beenreleased. Thus, the packer can be inflated by increasing thedifierential pressure between the bore of the drill string section andthe annulus to a first given magnitude, and deflated by increasing thedinerential pressure to a second given magnitude and quickly releasingthe pressure. After the packer has been inflated, the hydrostaticpressure below the packer on the drill string section can be decreasedto free the drill string from the walls of the borehole.

Objects and features of the invention not apparent from the abovediscussion will become evident upon consideration of the followingdetailed description taken in connection with the accompanying drawings,wherein:

FIGS. 1 and 2 are elevational views, partially in cross section, of adrill string positioned in a borehole, including BJZBJ i-B Patented Mar.3, 1964 apparatus in accordance with the invention illustrating twooperative positions of the apparatus during the course of freeing adrill string;

FIG. 3 is a cross-sectional view taken along section 33 of FIG. 1; and

FIGS. 4 and 5 are cross-sectional views of an embodiment of apparatus inaccordance with the invention illustrating two operative positions ofthe apparatus.

With reference generally to FIGS. 1-3, there is shown a drill string 1including drill collars 5 positioned in a borehole 2 penetrating a givenearth formation 4. The borehole is filled with drilling fluid or mud 3.The drill collars 5 include a section 11 near the upper end thereof, towhich fluid expansible packer 9 is afiixed. At the lower end of thedrill string is a bit sub 16, to which is afiixed a drilling bit 15,here shown as a fish tail bit including at least one port or nozzle 17for directing a jet of drilling fluid downwardly to facilitate drillingoperations. The drill collars 5 are shown as being stuck against theearth formation 4. The drill string is illustrated as having been raisedfrom the bottom of the borehole, such as is usual during a round tripfor the purpose of replacing a drill bit or while adding a joint ofpipe. It is during such operations that diiierential sticking often isencountered.

ln FIGS. 4 and 5 there is illustrated apparatus within drill collarsection 11 for the purpose or inflation and deflating packer h byselectively increasing and decreasing the hydraulic pressure within thedrill string. Packer 9 is shown as being afiixed to drill collar sectionill by means of a clamping ring 23. It will be assumed that a similarclamping ring is used to aifix the lower end of the packer to the drillcollar section l1. Between the interior surface of packer 9 and the bore2 2 of the drill collar section ii there are provide two passageways forfluid. The first passageway comprises passageway section 53, chamber s3,and port 65. The second passageway comprises passageway section 25,chamber 32, and port 34. The first passageway is normally closed by avalve in chamber 63, said valve including a valve stem 61 having anextension 5'? at the lower end thereof extending into passageway section53 for guiding and centering the valve stem. The valve stem 61 seats onthe tapered surface or seat s2 at the lower end of chamber 63 forclosing the passageway. A collar 6) is afiixed to valve stem 61. Ahelical compression spring 71 around the valve stem engages the upperend of chamber 63 and the collar 69 for urging valve stem 51 against thetapered seat 62:. The valve stem s1 extends through a wall 73 into achamber 75. The chamber has a port 14 for providing fluid communicationbetween chamber 75 and the exterior of the drill string above packer 9.An O-ring 74 is provided to seal around the valve stem 61 to preventfluid communication between chambers 63 and 75. Chamber 75 and port 14-perrnit valve stem 61 to be forced ofi of seat 52 when the pressuredifferential between bore 22 and the borehole around the drill collarsection 11 becomes sufficiently high to overcome the force of spring 71.When valve stem 61 is forced oil of seat 62, fluid will flow throughpassageway section 53, chamber 63, and port 65 to inflate packer 9 asshown in FIG. 5.

For the purpose of deflating packer 9 by the simple expedient ofincreasing the diflerential pressure between the interior of drillcollar section it and the annulus therearound and above packer 9, thereis provided a second valve arrangement in the second passagewaydescribed above. Valve stem 33 has a guide extension 27 thereonincluding an annular sealing member 29. The valve stem seats on thetapered valve seat section 31 of chamber 32. Aflixed to the upper end ofvalve stem 33 and forming an integral part of the valve stem are pistons35 and 47 connected together by connecting rod 41 35' is adapted toreciprocate in cylindrical chamber 39, and piston is adapted toreciprocate in cylindrical chamber 45. A helical compression spring 49in chamber engages the upper end of piston 47 to force the pistonsdownwardly in their chambers so that valve stem 33 will seat on valveseat 31. Within the between chambers 3? and 45 there is provided ewayincluding a check valve 41 for permitting fluid flow from criamoer 39 tochamber 45, but preventing fluid flow therethrough from chamber 5-5 tochamber 39. Also within wall is an orifice 43 for permitting limitedfluid flow in both directions between the chambers 39 and A light, cleanliquid of selected viscosity fills the portion of chamber 45 belowpiston 4-7 and fills the portion of chamber 39 above piston 35. A port13 permits free fluid communication between chamber 45 and exterior ofthe drill collar section Ill. Thus, when a given differential pressureexists between the bore of the drill collar section ill and the boreholeannulus above packer 9 sufficient to overcome spring 49, valve stem 53will pop ofl of seat 31. "l' he check valve 41 will open so that thevalve stem will be forced upwardly a substantial distance when it popsoff of seat 31. Check valve 41 will immediately close, and the valvestem 33 and pistons -5-7 and 35 will be forced downwardly very slowly byspring 49 because of the greatly restricted fluid flow through orifice43. Thus, the valve stem 33 will remain off of its seat 31 for apredetermined period of time determined by the dimensions of orifice 43.

The over-all operation of the apparatus illustrated in FIGS. 1-5 is asfollows. Let it be assumed that the drill string has become stuckagainst the wall of earth formation 4 as illustrated in FIG. 1. Aquantity of a light fluid, such as water, is circulated down the well toreduce the weight of the column of fluid in the drill string until thepressure exerted by the liquid in the drill string on the borehole wallbelow the packer is less than the formation pressure below the packer.in the usual case it will be found that 1600 to 2000 feet of Water inthe drill string bore at the top of the drill string will givesatisfactory results. Nitrogen or other relatively inert gas may be usedfor this purpose. A number of balls 21 (see FIG. 2), which may be ofrubber or a rubber-like material and of a diameter greater than thediameter of ports 17, are dropped into the drill string so as to sealthe ports 17. After the balls 21 have plugged the ports 17, pressurewithin the bore of the drill string is increased to a first pressurewhereat valve stem 61 is forced off of its seat. The fluid within drillcollar section 11 will flow through passageway section 53, chamber 63,and port 65 to inflate packer 9. This condition is illustrated in FIG.2. The pressure within the drill string may then be released to lowerthe pressure in the annulus below packer 9 to permit the drill collars 5to be freed from the earth formation 3. It has been found that once thedrill collars are freed they do not again tend to become stuck. Thereason for this is not completely under tood, but experience has shownthat it is consistently the case; see the article in the Oil and GasIi'ournal, supra.

The pressure in the drill string bore is again increased until valvestem 33 is forced off of seat 31. The pressure in the drill string thenis quickly decreased. Valve stem 61 immediately will reseat on seat 62.,but valve stem 33 will remain oil of seat 33 for a period suflicient forpacker 9 to deflate. The drill string then may be retracted from theborehole or may be lowered to the bottom of the borehole so thatdrilling operations may be recommenced, as desired.

If it is desired to resume drilling without removing the drill stringfrom the borehole, the pressure in the drill string bore is increaseduntil the balls 21 extrude through ports 17. Manifestly, if it iscontemplated, the balls should be formed of relatively soft rubber.Alternatively, the direction of drilling fluid circulation can bereversed so Valve piston that the balls are carried up the drill stringbore to the earths surface.

It is to be noted that during normal circulation the pressure inside thedrill string will be greater than the pressure in the annulustherearound because of the pressure drop across the ports in the bit.Therefore, it is manifest that the constants of springs 49 and 71 shouldbe chosen so that the pressures required to operate valves 26 and 54will be greater that the maximum circulating pressure.

The invention is not to be restricted to the specific structural detailsor arrangement of parts herein set forth, as various modificationsthereof may be effected without departing from the spirit and scope ofthe invention.

We claim:

1. For use with a tubular drill string having a fluid expansible annularpacker affixed to the outer surface thereof, constructed and arranged sothat fluid pressure exerted on the inner surface thereof will expandthepaclter to the walls of a borehole within which the drill string isdisposed, apparatus for controlling application of fluid pressure fromthe bore of the drill string to the inner surface of the packer,comprising:

a drill string section for supporting the packer;

first and second passageways in the drill string section between thebore of the drill string section and the inner surface of the packersupported thereby;

first, normally-closed valve means in said first passageway forcontrolling fluid pressure therethrough, constructed and arranged toclose said fluid passageway while the pressure within the drill stringsection bore is greater than the pressure in the borehole annulus andwhile the dilferential pressure between the drill string bore pressureand the borehole annulus pressure is less than a first givendifferential pressure, and to open when the pressure within the drillstring section bore is greater than the pressure in the borehole annulustherearound and said differential pressure between the drill string boreand the borehole annulus reaches said first given diflerential pressure;

second normally-closed valve means in said second'passageway forcontrolling fluid flow therethrough, constructed and arranged to closesaid fluid passageway while the pressure within the drill string bore isgreater than the pressure in the borehole annulus and the differentialpressure between the pressures in the drill string bore and the annulusaround the drill string section above the packer is less than a secondgiven differential pressure greater than said first given dilferentialpressure, and to open when said differential pressure between the drillstring bore pressure and the borehole annulus pressure reaches saidsecond differential pressure; and

means connected to said second valve means for holding open said secondvalve means for at least apredetermined time interval after thedifferential pressure between the drill string section bore and theborehole annulus above the packer falls to less than said seconddifferential pressure.

2. For use with a tubular drill string having a fluid expansible annularpacker affixed to the outer surface thereof, constructed and arranged sothat fluid pressure exerted on the inner surface thereof will expand thepacker to the walls of a borehole within which the drill string isdisposed, apparatus for controlling application of fluid pressure fromthe bore of the drill string to the inner surface of the packer,comprising:

a drill string section for supporting the packer; first and second fluidpassageways in said drill string section connected in parallel betweenthe bore of said drill string section and the exterior of said drillstring section under the packer; a first chamber in said drill stringsection in fluid communication with the exterior of said drill stringsection and separated from said first passageway by a first wall;

a second chamber in said drill string section in fluid communicationwith the exterior of said drill string section and separated from saidsecond passageway by a second wall;

a first valve seat positioned in said first passageway, and

a second valve seat positioned in said second passageway;

a first valve stem in said first passageway, extending through saidfirst wall from said first chamber, for seating on said first valve seatto norma l close said first passageway;

a second valve stem in said second passageway, ex-

tending through said second wall from said second chamber, for seatingon said second valve seat to normally close said second passageway;

first spring means engaging said first valve stem and said drill stringfor urging said first valve stem into seating engagement with said firstvalve seat;

second spring means engaging said drill string section and said secondvalve stem, adapted to hold said second valve stem on said second valveseat against a greater differential pressure between the bore of thedrill string section and the exterior thereof than can be resisted bysaid first spring in holding said first valve stem on said first valveseat; and cans in said drill string section for holding said secondvalve stem off of said second valve seat for at least a predeterminedtime interval after said second valve stem has been lifted olf of saidsecond valve seat.

3. For use with a tubular drill string having a fluid expansible annularpacker afiixed to the outer surface thereof constructed and arranged sothat fluid pressure exerted on the inner surface thereof will expand thepacker to the walls of a borehole within which the drill string isdisposed, apparatus for controlling application of fluid pressure fromthe bore of the drill string to the inner surface of the packer,comprising:

a drill string section for supporting the packer;

first and second fiuid passageways in said drill string sectionconnected in parallel between the bore of said drill string section andthe exterior of said drill string section under the packer;

a first chamber in said drill string section in fluid communication withthe exterior of said drill string section and separated from said firstpassageway by a first wall;

a second chamber in said drill string section in fluid communicationwith the exterior of said drill string section and separated from saidsecond passageway by a second wall;

a first valve seat positioned in said first passageway, and

a second valve seat positioned in said second passageway;

a first valve stem extending through said first wall from said firstchamber for seating on said first valve seat to normally close saidfirst passageway;

a second valve stem extending from said second wall to said secondchamber for seating on said second valve seat to normally close saidsecond passageway;

first spring means engaging said first valve stem and said drill stringsection for urging said first valve stem into seating engagement withsaid first valve seat;

second spring means engaging said drill string section and said secondvalve stem adapted to hold said second valve stem on said second valveseat against a greater differential pressure between the bore of thedrill string section and the exterior thereof than can be resisted bysaid first spring in holding said first valve stem on said first valveseat;

a piston engaging the walls of said second chamber and connected to saidsecond valve stem for reciprocating movement therewith; and

an orifice in said second wall for permitting fluid flow therethrough,and a passageway including a check valve in said second wall forpermitting fluid flow through said second wall into said second chamberwhen said second valve stem is lifted off of said second valve seatwhereby said second valve stem remains olf of said second valve seat forat least a predetermined period after said second valve stem has beenlifted oif of said second valve seat.

4. For use with a tubular drill string having a fluid expansible annularpacker afilxed to the outer surface thereof constructed and arranged sothat fluid pressure exerted on the inner surface thereof will expand thepacker to the walls of a borehole within which the drill string isdisposed, apparatus for controlling application of fiuid pressure fromthe bore of the drill string to the inner surface of the packer,comprising:

a drill string section for supporting the packer;

first and second fluid passageways in said drill string sectionconnected in parallel between the bore of said drill string section andthe exterior of said drill string section under the packer;

first valve means positioned in said first passageway and having aportion thereof exposed to borehole pressure around said drill stringsection in the vicinity of said packer constructed and arranged to closesaid first passageway until pressure in said drill string section boreis greater by a first predetermined pressure than the borehole pressurein the vicinity of said packer;

second valve means positioned in said second passageway and having aportion thereof exposed to borehole pressure above said packerconstructed and arranged to close said second passageway until pressurein said drill string section bore is greater by a second predetermineddifierential pressure than the borehole pressure immediately above saidpacker, said second predetermined difierential pressure being greaterthan said first predetermined differential pressure; and

means in said drill string section for holding open said second valvemeans for at least a predetermined time interval.

References Cited in the file of this patent UNITED STATES PATENTS2,497,185 Reistle Feb. 14, 1950 2,942,667 Blood et a1. June 28, 19602,994,378 Reistle Aug. 1, 1961

1. FOR USE WITH A TUBULAR DRILL STRING HAVING A FLUID EXPANSIBLE ANNULAR PACKER AFFIXED TO THE OUTER SURFACE THEREOF, CONSTRUCTED AND ARRANGED SO THAT FLUID PRESSURE EXERTED ON THE INNER SURFACE THEREOF WILL EXPAND THE PACKER TO THE WALLS OF A BOREHOLE WITHIN WHICH THE DRILL STRING IS DISPOSED, APPARATUS FOR CONTROLLING APPLICATION OF FLUID PRESSURE FROM THE BORE OF THE DRILL STRING TO THE INNER SURFACE OF THE PACKER, COMPRISING: A DRILL STRING SECTION FOR SUPPORTING THE PACKER; FIRST AND SECOND PASSAGEWAYS IN THE DRILL STRING SECTION BETWEEN THE BORE OF THE DRILL STRING SECTION AND THE INNER SURFACE OF THE PACKER SUPPORTED THEREBY; 